Approximately 200,000 people in the US will develop a brain metastasis each year. Patients with well-controlled systemic disease are candidates for local therapy such as surgical resection or stereotactic radiosurgery. Randomized trials have shown that surgical resection of solitary brain metastases improves survival and duration of functional independence. Retrospective cohort studies suggest that stereotactic radiosurgery may offer a comparable survival benefit. The assessment of quality of life (QOL) in these studies has been rudimentary. Neurosurgeons, oncologists, patients, and families are increasingly focused on the importance of QOL for cancer patients. We propose a prospective study of a cohort of patients with solitary brain metastases receiving either surgical resection or stereotactic radiosurgery. We will use "preference-based" QOL measurement techniques (e.g., standard gamble, EuroQol 5D) to measure QOL using a modification of Q-TWiST (a method of combining survival and QOL in cancer patients to obtain quality-adjusted survival) that incorporates the preference-based QOL values, we will calculate the quality-adjusted survival in the two treatment groups. We will explore the relationships between quality-adjusted survival and cognitive status, depression, functional status, disease presentation, and treatment. Comparing quality-adjusted survival associated with surgical resection and stereotactic radiosurgery should provide valuable information for patients, families, oncologists, and neurosurgeons considering treatment alternatives for metastatic brain tumors. Although the ultimate goal of cancer research is to eliminate and cure cancer, we propose to provide pilot data eventually leading to Class I evidence supporting a specific treatment modality for patients with brain metastases based not alone on survival but quality of life and quality-adjusted survival.